3-氨基苯酰胺对氧化应激诱导的HeLa细胞端粒DNA链断裂重连接作用的影响

端粒是位于真核细胞染色体末端的DNA-蛋白质复合体，在维持染色体稳定上起着重要的作用，并且与细胞的衰老和凋亡有着密切的关系.在各种DNA损伤中，单链断裂(single-strand breaks, SSBs)是最常见的类型之一，既可直接通过内源活性氧或离子化辐射产生，也可间接地在DNA代谢或碱基切除修复期间产生.已知多聚(ADP-核糖)聚合酶［poly(ADPribose) polymerase, PARP］在SSBs修复中起着极为重要的作用.本实验观察了PARP抑制剂3-氨基苯酰胺(3-aminobenzamide, 3-AB)对氧化应激诱导的HeLa细胞端粒DNA链断裂重连接的效应以及对过氧化氢(H2O2)抑制HeLa细胞增殖的影响.结果表明3-AB能够显著地抑制氧化应激诱导的HeLa细胞端粒DNA链断裂后的重连接作用，并能增强H2O2对HeLa细胞增殖的抑制作用，提示PARP参与了端粒DNA链断裂损伤的修复过程.

Effects of 3-Aminobenzamide on Rejoining of Telomeric DNA Strand Breaks Induced by Oxidative Stress in HeLa Cells

Telomere,the DNA-protein complex at the end of eukaryotic chromosome,plays an important role in maintenance of chromosomal stability and is closely related with cell senescence and apoptosis.Among various DNA impairments,single-strand breaks(SSBs)is one of the most frequent impairments.SSBs can occur either directly by endogenous reactive oxygen species and ionizing radiation or indirectly in the process of DNA metabolism and base excision repairing.The poly(ADP-ribose)polymerase(PARP)has been proposed to play a key role in SSBs repairing.In the current study,the effects of 3-aminobenzamide(3-AB),a PARP inhibitor,on the repair of telomeric DNA strand breaks induced by oxidative stress and the inhibition of cell proliferation by hydrogen peroxide(H_2O_2)in HeLa cells were analyzed.The results showed that 3-AB strongly inhibited the rejoining of telomeric DNA strand breaks and enhanced the inhibition of H_2O_2 on cell proliferation.The results indicated that PARP might be involved in the repair of telomeric DNA strand breaks damage.